1. Field of the Invention
The invention relates generally to communication systems and, more particularly, to correcting in-phase (I) and quadrature-phase (Q) imbalances in a receiver.
2. Related Art
IQ imbalances are a problem for conventional receivers that generate separate I and Q output signals. IQ imbalances can be caused by non-identical I and Q paths in such receivers. For example, factors such as local oscillator quadrature mismatch, gain and phase mismatch in amplifiers, and filters and analog-to-digital converters (ADC) in the I and Q paths can all contribute to IQ imbalances. The IQ imbalances can be frequency-dependent imbalances (i.e., that vary with frequency) or frequency-independent/direct current (DC) imbalances (i.e., that do not vary with frequency). Uncorrected, IQ imbalances can cause signal detection errors, which detrimentally impact receiver performance.
What is needed, therefore, is an apparatus and method for correcting frequency-dependent and frequency-independent IQ imbalances in a receiver.